Master Scheduling

The purpose of master scheduling is to analyze and release planned work orders that have either been generated automatically or entered manually.

Before you start

Master scheduling can begin when one or more of the elements producing a maintenance demand exist (see diagram below). In addition, the following prerequisites must be met.

  • The object (product) must exist in 'Item. Open' (MMS001) and, must be the object on which the service is to be performed.
  • The structure type must be defined in 'Product Structure Type. Open' (CRS087).
  • The service must be defined in 'Service. Open' (MOS300) with status 20. Also, the service may not be defined as a sub-service.
  • The service must also be registered in 'Service. Connect to Facility' (MOS301). Here it must be entered as belonging to the facility or consolidated facility. Also, the planning policy order type must be specified and the lead time updated from the product structure.

Follow these steps

The diagram below illustrates the activities involved in master scheduling. Master scheduling involves analyzing the planned work orders, in some cases combining them into a workscope, and ultimately ends with releasing the planned work orders. After release they become actual work orders. Each of the activities is described below in further detail.

Maintenance Demand

As indicated in the diagram above, maintenance demands are derived from a number of sources. They include both long term scheduled maintenance (that is, operation plan, service definition) as well as short term maintenance and repairs (customer and engineering orders).

  • Service Definition

    Scheduled or planned services are defined in 'Service. Open' (MOS300). The way in which the service is defined, as well as the structure (parts and operations) directly affect how the master schedule is generated.

    For each service, different limits can be defined in 'Service. Connect Maintenance Limits' (MOS311) specifying the interval at which the services are to be performed. A service can also be related to one or more services. If the relation is mandatory, a planned WO will be created for both the initial WO and the related service(s).

  • Operation Plan

    For each aircraft, an operation plan must be created in 'Operation Plan. Open' (MOS380) enabling future maintenance demands to be forecasted. The operation plan is compared to the maintenance limits and defined for the various services, resulting in the generation of planned WOs.

  • Actual Operation

    Actual usage is registered in 'Operational Log. Open' (FLS001). The flight log contains information about aircraft usage in the form of meters defined for the aircraft (for example, flight hours, flight cycles).

    Based on the vehicle structure, the operational values of components (substructures/components) are updated according to the information registered for the vehicle.

  • Engineering Orders (EO)

    Engineering orders are entered in 'Engineering Order. Open' (MOS200). For each EO, an EO line must be created in 'Engineering Order. Open Lines' (MOS210). The EO line is a direct link to 'Service. Open' (MOS300) where the service (line) must be registered.

    For repetitive EOs, the interval limits must be defined in 'Service. Connect Maintenance Limits' (MOS311). Once the limits have been registered, the EO is processed the same as a normal service. However, when reporting is performed for the service, the modification history of the object is updated.

    For non-repetitive EOs, an EO program can be generated in 'Eng Order. Retrieve Affected S/N' (MOS910). Once generated, a list of the objects affected by the EO can be displayed in 'Eng Order. Update Affected Serial No' (MOS220). Planned WOs can be created directly from the list of affected objects.

  • Customer Orders and Customer Order Quotations

    Once a customer order is entered, it is included in the calculation of the master schedule. Both normal customer orders (status 20) and customer order quotations (status 10) are included in the master schedule. However, it is only possible to release a planned WO derived from a customer order whose status is 20.

    Note: this functionality is planned for future release.

  • Forecasted Orders

    At present this functionality has not been defined.

  1. Master Schedule Generation

    The master schedule is calculated based on parameters defined in 'Settings - Maintenance 1' (CRS788). In particular, the parameters define the demands that are to be included in the generation of the master schedule. These include scheduled services, unscheduled services, engineering orders and external work orders (customer service orders).

    In 'Master Schedule. Regenerate' (MOS999), the master schedule can be regenerated per facility, item or lot number at any time. The planning horizon and generation methods can be specified to best fit planning needs.

    Create Planned Work Order

    Planned WOs can be created manually in 'Work Request. Open' (MOS170). Each planned WO consists of the object on which the service is to be performed (often both the product no. and the serial no.), the structure type and the service itself. The service must, of course, be registered in 'Service. Open' (MOS300).

    The planned WO is assigned a status by default according to the planning policy set for the service in 'Service. Connect to Facility' (MOS301). The status can have the following meanings.

    Planned WO status (MOS170)

    00 Error - no material requirements generated
    05 Assigned due to database warning - material requirements generated.
    >20 Firm planned order – manually assigned. System cannot delete or change proposed dates.
    60 Released work order – manually or automatically assigned. Will be transferred to 'Work Order. Open' (MOS100).

    If a planned WO is created directly from 'Complaint. Open' (MOS500), the Complaint ID will be updated in (MOS170/E). Once planned WOs have been created, they can be analyzed and then released.

  2. Planned Work Order Analysis

    This activity analyzes the planned WOs with regards to material availability, tool availability, work center capacity, meter values, etc. Planned WOs may be combined together into a workscope. The activity can also involve adding related services (non-mandatory).

  3. Release Planned Work Order

    After analysis of the planned WOs is complete, the orders can be released and an actual work order created. When an order is released, the related planned WOs are released simultaneously. The same applies for a planned WO belonging to a workscope; if one planned order belonging to a workscope is released, the other orders are released as well.

    Once the orders are released, they are assigned status 60. They are then transferred to 'Work Order. Open' (MOS100) where detailed shop floor planning can be performed.

    While it is possible to forecast work orders based on on-condition requirements, they may not be released. This type of planned WO is instead consumed when the work orders are created manually.

  4. Change Order Specification

    For preliminary orders, the product structure that is used for calculating the lead time, planned load, material reservations etc., is the structure that is defined in the product basic data.

    When a preliminary order is released, the product structure in the product basic data is copied into the production database. If changes are to be made to the material or operations for a single order only, they must be made after the order has been released. Changes to the order are made in 'Work Order. Open' (MOS100).